Hollies (Ilex spp.) are a varied group of trees and shrubs. Whether evergreen or deciduous, hollies are valued in home landscapes for their sturdiness, graceful habit and ornamental berries. Holly bushes make excellent hedges and screens and are good foundation plants as well. Hollies are easy to grow shrubs, especially when well-fed.
Hollies grow best when fed with a fertiliser specially formulated for acid-loving plants. The nitrogen-phosphorus-potassium, or NPK, ratio in such fertilisers should be balanced, with the proportions roughly equal. Careful feeding is especially important for young hollies still establishing themselves in the landscape since they grow quickly and have strong growth when well-fertilised. Hollies require acid soil with a pH between 5.0 and 6.0 since their roots most easily absorb nutrients from soil in that pH range.
Espoma's Holly-tone was the first commercial plant food specially formulated for hollies and other acid-loving plants. The company recommends feeding hollies twice yearly, in spring and fall. Package directions call for shrubs under 3 feet in diameter to be fed in spring with 1 cup of Holly-tone per foot of diameter; plants 3 feet or more in diameter need 2 cups of product per foot. The fertiliser is sprinkled around the drip line -- the area under and slightly past the spread of the branches -- and then watered in. Fall feeding is half the amount of the spring rate. Holly-tone is an organic, granular product with an NPK ratio of 4-3-4 and is available in 4-, 8-, 20- and 18.1kg. bags; 0.454kg. equals 3 cups of fertiliser.
The Scotts Miracle-Gro Company makes two products suitable for use on holly bushes. Miracid is for gardeners who prefer water-soluble fertilisers. Because the product can be sprayed onto the leaves as well poured onto the soil around the roots, nutrient absorption is much quicker than with granular products. The recommended solution rate is 1 tbsp per gallon of water, to be applied to the plants every seven to 14 days during the growing season. As with all water soluble fertilisers, never use a stronger solution than recommended or you risk burning the foliage and roots on your plant. Miracid is available in 1- and 1.81kg. boxes. It's NPK ratio is 30-10-10 before dilution.
Miracle-Gro also offers a granular fertiliser called All Natural & Organic Holly Food. It's formulated with feed-grade ingredients, doesn't contain manure, and has an NPK ratio of 3-4-3. The recommended application rate is 0.907kg. of fertiliser per 100 square feet, spread over the soil or mulch and watered in. The product needs to be reapplied every two months during the growing season. It's available in 4-, 8- and 9.07kg. bags.
Acid Adoring by Bradfield Organics is a coarse powder fertiliser with an NPK ratio of 4-5-4. It's made with feed-grade ingredients and has no animal manure included. Acid Adoring is available in both 5- and 11.3kg. bags; 0.454kg. equals 2 cups of product. Established hollies should receive monthly applications of 1 cup of Acid Adoring for each foot of plant height or diameter during the growing season.